The studies of melanoma-prone families, families with multiple endocrine neoplasia type I, and nevoid basal cell carcinoma syndrome have continued. Members of the section have contributed data to and participated in the Genetic Analysis Workshop VII. Case-control studies of lung cancer and bladder cancer with biochemical components have continued, and a case-control study of melanoma was initiated and moved into the field. A cohort study of the risk of second cancers after ovarian cancer was continued. Research on mathematical aspects of linkage analysis procedures continued with the development of methods to determine identity-by descent sharing of genotype in pedigrees and a multivariate linkage procedure.